Electrolytic cell



H. l. ALLEN AND K. H. FOX.

ELECTROLYIIC CELL. APPLICAHON FILED APRL2. 19m.

Patented Aug. 17, 1920.

A I" .Il

4M Q ,f 7 m. l. /H w, a i. n wm H.1.ALLEN AND K. R. EUX.

ELECTRGLYTLC CELL. APPUCAUOM man APR.2.`19\9.

Patented A110'. 17, 1920.

1 a l J u wm u l 1 z z f l l LVIhILLsLML1- H. l. ALLEN AND K. R. FOX.

ELECTROLYTIC CELL.

APPucArloN mw APR.2,19|9.

1,349,597. Patented Aug. 17, 1926.

3 SHEETS-SHEE] 3.

UNITED STATES PATENT OFFICE.

HERBERT I. ALLEN AND KENT B. FOX, OF PORTLAND, MAINE, ASSIGNORS TOELECTRON CHEMICAL COMPANY, OF PORTLAND, MAINE, A

OF MAINE.

CORPORATION ELECTROLYTIC CELL.

Specioation of Letters Patent.

Patented Aug. 17, 1920.

Application filed April 2, 1919. Serial No. 286,950.

This invention has for its object to provide an electrolytic cellofgsimple construction, in which the cathode and anode are soconstructed and arranged as to afford a maximum conducting surface forthe palsage of the current through the electrolyte, and ,in whichcertain other advantages will be obtained as hereinafter made plain.

In the embodiment of the invention selected for illustration anddescription, the tank is oblong in plan view. Resting thereon is thefree-board section in which the chlorin is collected, and in which theremay be a columnof the electrolyte to increase the hydrostatic head.To-the under side of the free-board section is attached the cathodewhich lis in the shape of a rectangular box or basket approximating theshape of but smaller than the tank, and whichV is suspended from thefree-board section into the tank. By removing the free-board section,theicathode and the anode may be removed bodily therewith from the tank.The boxlike cathode is made of sheet iron and its sides, ends andbottoms are provided With numerous perforations for te passage of thesolution of brine and caustic and of the hydrogen. Within the cathode isan anode with side, end and bottom faces confrontlng the correspondingparts of the cathode and Referring now to the accompanying draw.

figure 1 represents, in vertical longitudinal section, an electrolyticcell embodyingr our invention. Y

Fig. 2 represents a plan view thereof.

Fig. 3 represents a horizontal section through the cell.

Fig. 4 represents n tion through the cell.

Fig. 5 shows the cathode detached.

Fig. 6 shows a section on a larger scale, through one of the boltsl byWhich the cathode is attached to the upper free-board sectransversevertical section of the cell, and shows how the cathode and the marginof the diaphragm are clamped thereto to make a Water-tight and gas-tightjoint.

Fig. 7 is a section of the cathode on a 60 large scale, showing how thediaphragm is arranged to cover the slde and bottom walls thereof.

The cell, as shown, comprises the tank which is preferably made of ironor steel'65 sheets or plates, and which as stated is oblongr in planview. lt has the bottom 10 with an upturned marginal flange 11 to whichare riveted the plates or sheets (one or more) which are ends 12 andsides 13. From the bottom of the. body leads a pipe 14 for conductingaway the products of the electrolytic decomposition of the electrolyte.

The free-board section of the cell is preferably made of slabs of slate,cast concrete or other inert material, of the proper dimensions, whichare secured together in any convenient way to constitute the end Walls15 and Side Walls 16, flush with the corresponding walls 12 and"13 ofthe tank. The upper end of the free-board section is closed by a coverconsisting of a slab or plate 17 of similar material inert to chlorin.This cover is provided with holes to receive the feeding 35 tube 18, andthe nipple 19 with which the conduit 20`is connected for conducting awaythe chlorin.

The cathode 21, as has been described, consists of a sheet metal box orbasket (preferably iron) havingr a bottom Q2, sides 23 and ends 24, andit is of such dimensions as to fit within the tank and be spaced fromthe walls and bottom thereof, as shown in Fig.

l. All of the walls of the cathode are provided with numerous closelyspaced perforations,preferably small slots in herringbone. formation. Attheir' upper edges. the end and side Walls of the cathode are providedwith out-turned marginal [langes 25. rentrant angles 2G at the cornersof the box are filled with square plates 27, Whose upper surfaces arelocated above those of the flanges a distance about equal to thethickness of the diaphragm when the latter is under compression. Thepurpose of the flange will be subsequently explained; and it willsuffice here to state that it is preferably in Width substantially equalto the widths of the side and end walls of the freebent to constitutethe 70 The 100 hoard section of the cell. The cathode tapers downwardlyas indicated in Figs. l and 4.

'itbin the cathode is arranged a diaphragm to cover the side, end andbottom walls thereof. lreferably the diaphragm consists of one or morelayers or strips of porousI asbestos pa per 2H laid lengthwise on thebottom of the cathode, uml then bent upwardly so as to cover the endwalls thereof as shown in Fig. l, with its extremities bent outwardly tooverlap the end liauges. The inner faces of the side walls of thecathode are likewise covered by sheets 2l) of asbestos which terminateat and cover the bottom of the cathode (so as to furnish a double layerthereon) and which have their upper extremities overlapping on the sidefiangcs 25. 'l'he reiintrant angles, forlned by the sheets at thecorners, are filled by the plates or blocks 2T. A rectangular frame ISUof iron (either a casting or four bars suitably connected) is employedto clamp the flange of the cathode and the diaphragm to the under side.of the free-board sec-tion of the cell. Bolts 3l are passed throughapertures in cover and in the sides and ends ot' the freeboard sectionand are secured into the rec tangular frame, and on the ends whichproject upon the cover are nuts 32, by tightening which the frame, thecathode, the margins of the diaphragm, the free-board section and thecover may all he clamped rigidly together. The frame merely rests uponthe upper edges of the walls of the tank, so that it and the partsconnected thereto may be removed as a unit from said tank. The flanges:$5 are imperforate, and the margins of the diaphragm between them andthe wallsl l5, 1G, serve as packing and make a gas and liquid-tightjoint to prevent the escape of liquor or gas. lf desired, the marginsmay be impregnated with an insulatingr material inert to chlorin.W'ithin the cathode and the diaphragm there is located the anode whichconsists of the. elongated carbon or 4h'heson graphite plates 33whiehare shown as eight in number, with a set of four plates closelyconfronting each side wall of the cathode and spaced from the other set.These. plates are secured by earbon or graphite pins 3,4 to the upright`carbon bars or rods 35 which Space the sets apart and which projectupwardly from and through the cover 1i". Said rods have connected totheir exposed endsa bus bar 36 to which the positive lead \\'ires of thecircuit are connected. The anode may be hung from the cover, butpreferably it rests upon transverse supports 37 of insnlatingvmaterialsuch as glass., porcelain or other inert substance placed upon thebottom offthe cathode. At the ends ofthe two sets o'l' carbon plates orslabs 2&3, there are blocks or bars Srl of carbon or graphite, whiin areflush with the en'd faces of said plates or slabs 33, so as to forni endfaces or conducting surfaces coufrontilu,r the surfaces or faces of the.end walls of the cathode. The anode is thus in the shape, roughly, of anoblong rectangular tube which `is open at theitop and bottom to permitthe circulation of the electrolyte downwardly therethrough and upwardl.through the spaces between the sides and ein s of the anode and thecathode. 'lhe bottom surfaces or faces of theanode` confront the activebottom wall ofthe cathode, so that (except for the space between the twosets of anode plates) there is a maximum conducting surface. for thepassage of the currcnt through the electrolvte to the cathode. At oneend of the cathode, the flange 2] is bent upwardly to provide a plate orextension 40 to lie outside of and parallel with thi.l freedioardsection of the cell as shown in Figs. l and 5. rl`o tliis plate issecured a bus bar -ll with which the negative lead wire of the circuitis secured.

lt will bc understood` of course, that anv suitable. inert cement orother packing mahterial is used to close any spaces between the walls ofthc apertures of the cover and the members which pass thereinto, such asthe feed well 18, the anode bars 35, and the gas nipple 1S), to preventthe escape of free ohlorin into the` atmosphere.

In practice, the sodium chlonid solution is fed continuouslyY into thefeedwell (which has an ednction port or aperture 43 at its lowersubmerged end) from the usual float valve. the level of the electrolyteheilig maintained preferably below the top of the cathode and above thetops of the anode plates. The electrolyte pereolates through the porousdiaphragm into contact with the perforated side, end and bottom walls ofthe cathode. The caustic soda resulting from the reaction, together withthe undecomposed brine, flows or drops into the bottom of the tank, andis colltinuouslv conducted away therefrom through the discharge oreduction pipe 14 for concentration and eva poration of the causticsolution and removal of the salt therein contained. liberated on thesurfaces of the anode is collected in the free-lmard section of the celland conducted away through the nipple 19 and the conduit 2u.

The. faces of the anode are close to the confronting faces of thecathode. the spaee between them decreasing in width downwardly tocompensate for the resistance of the. anodes.

lt is of course evident that` although we have described the cell asused for the elec` trolysis of an aqueous sodium chlorid Solur tion. itmay be en'iploved for the electrolytic dcconiposition of other suitablechemical compounds.

From thc foregoing description which we The chlorin have given of thecell, it will be apparent to those who are skilled in the art that thereare certain advantages resulting therefrom. It may be noted, forinstance, that practically the entire inner face of the cathode,including the bottom, sides and end walls, is electrically active, andthat the exterior faces ofthe cathode are wholly nnsubmerged in any bodyof electrolyte, the eduction pipe serving to insure the removal from thetank of the eiliuent from the cell. The fianges of the cathode are solidand not perforated, but the perforations in the side and end wallsterminate at the corners formed by the lianges and said walls, so thatevery )art of the cathode which is in contact witli the electrolyte isperforated so as to permit the, free flow of the electrolyte and theemission of the hydrogen which is liberated at the inner faces of thecathode outside of the diaphragm. By providing a water-tight andgas-tight pressure joint between the cathode and the free-board section,it is possible to build up the column of electrolyte in said free-boardsection so as to secure thc desired hydrostatic head as the diaphragmbecomes more or less clogged with the impurities in the l 'ine, thusinsuringr a longer diaphragm life than would otherwise be possible. Thehydrogen, which collects in the tank. escapes through whatever crevicesthere may be between the top edges of the walls thereof and therectangular frame which rests thereon. but, if desired, of course, thetank ma)r be provided with a pipe outlet for conducting away andutilizing the hydrogen, in which case of course a suitable packingmaterial may be interposed between the rectangular frame and the top ofthe tank.

T he bottom of the cathode is preferably provided with at least twolayers of the asbcstos sheets constituting the diaphragm so that thetiow through the diaphragm and cathode will be equaliacd by checking theHow through the bottom. The presence of the tank is of course desirableto prevent thc admission of air to the hydrogen-containing spaceexterior of the cathode and to prevent the formation of carbonates.

Theoretically the best results are secured only when there are maximumsurfaces of cathode and anode in provimit)7 with the electrolyte betweenthem so that all part-s ot' the cathode and anode arc. electricallyactive, for, where portions of the cathode or cell body are inactive,deterioration soon sets in and the efficiency of the cell is lowcrcd.There is another consideration, however. to wit, that in order toprevent wastage of the current. there shall be a constant supply ofsaturated brine. ln the cell, which we have herein described, it will beapparent that we not only provide for the free, How of brine to theactive surfaces of cathode.

the anode and cathode, but that this is accomplished without diminishingto any material extent Vthe active surface of the To allow for the freepassage of the electrolyte from one portion of the anode chamber toanother, the anode is, as previously stated, submerged slightly at leastin the electrolyte, and at the bottom of the anode there is an openspace through which the electrolyte may pass. lf desired, of course.,the anode plates may be thicker so as to decrease the opening orpassageway therethrough, and thus increase the active anode surface. lVehave found that the relative proportions, as illustrated in thedrawings, are desirable in that they provide for the presence of arelatively large body of electrolyte to prevent its tot rapidimpoverishrnent of salt, which of course would impair the efficiency' ofthe cell.

le should not regard it as a departure from the spirit and scope of theinvention if the tank were filled with oil or other liquid ilnmisciblewith the caustic eflluent, and by reference to the cathode beingexteriorly unsubmerged we have in mind a construction in which theexterior faces (side, bottom and the end Walls) of the cathode are notin contact with an accumulation of the cell etliuent.

Having thus explained the nature of our said invention and described away of making and using the same, although without attempting to setforth all of the forms in which it may bc made or all of the modes ofits use, what we claim is:-

1. An electrolytic cell comprising a suit- I able tank, a rectangularbox-shaped cathode having perforated active end, side and bottom walls,a diaphragm covering the inner faces of all of said walls, andarectangular tubular anode of similar cross section disposed within thecathode, supported on the bottom thereof, and havingV end. side andbottom faces confronting and spaced from the like active faces of thecathode.

An electrolytio cell comprising a` su`table tank, a rectangularbox-shaped cathode having active end, side and bottom walls all providedwith perforations, a diaphragm covering all the inner faces of thccathode walls, a rectangular tubular anode disposed within the cathodeand having active faces confronting and spaced from the active sidc,bottom `and end walls of the cathode.

3. An electrolytic cell comprising a rectangular tank. a removablerectangular f reeboard or top section resting thereon, a bo like cathodeclamped to and suspended from said free-board section and havingperforated side, end and bottom walls. a diaphragm covering the innerfaces of said walls and clamped between the cathode and said free-boardsection, and an anode arranged within said cathode and having activeside, end and bottom faces confronting and spaced from the inner facesof the corresponding walls of said cathode.

4. An elcctrolytic cell comprising a suitable tank with means fordischarging the cilluent therefrom to prevent the accumulation oi' thectllnent. a tubular cathode and a tubular anode therein, said tubularcathode having active bottom and side walls which are externallyunsubmerged and are spaced from said tank and also from said anode.

An electrolytic cell comprising a tubular open-end anode, the sheetmetal tubular cathode ninclosing and underlying the anode, and havingits sides and bottom perforated and exteriorly unsubmerged, a diaphrafmcovering ,the inner faces of the sides and bottom of the cathode, and atank in which said cathode is suspended with the sides and bottom spacedfrom the walls of said tank.

(i. An electrolftic cell comprising a tubular open-end anode, a tubularcathode int-[osing and underlying the anode, and-having its sides andbottom perforated and extcriorly unsubmerged, a diaphragm covering theinner faces of the sides and bottom of the cathode, in combination witha tank a free-board section resting thereon, and nic-ans for connectingthe cathode and freeboard section bya liquid-tight joint, whereby saidcathode is suspended from the freeboard section in the tank with theWalls of the cathode spaced from the walls of the tank.

7. An elcctrolytic cell comprising a tank a free-board section removablysupported upon the upper ed e of the tank, a cathode foi-ined as a metalasket having perforated side, bottom and end walls, and having outturncdmarginal flanges at its upper end, a porous diaphragm covering all theactive faces of the cathode and having marginal edges out-turned oversaid marginal flanges, clamp bars secured to said free-board section toclamp the out-turned edges of the diaphragm and the out-turned flangesof the cathode to the free-board section to form a substantiallygas-tight joint and enable the cathode to be suspended from thefreeboard section into the tank, and an anode within the cathode andhaving active faces confronting and spaced from the active faresthereof.

S. An f-lcctrolytic cell comprising a tank, a cathodiformed as a metalbasket suspended within said tank and having perforated bottom, side andend walls spaced fron. the walls of said tank. an anode occupying theinterior of said cathode and supporird on thi` bottom thereof, andinsulating nrc-.ins interposed between said anode and the porterait-dmetallic bottoni Wall of said lia-'liet` cell compri-ing a cathodeformed as a rectangular basket with perforated end, bottom and sidewalls, a diaphragm covering the inner faces of said walls, a free-boardsection from which said basket is suspended, a tank on the upper end ofwhich said free-board section rests with the walls of the cathode spacedfrom the walls of the tank, and a tubular anode occnpyln the space insaid cathode with active si e, bottom and end faces confronting butspaced from the corresponding active Walls of said cathode.

10. An electrolytic cell comprising a cathode formed as a rectangularbasket with perforated end, bottom and side walls, a d1aphragm coveringthe inner faces of said Walls, a free-board section from which saidbasket is suspended, a tank on the upper end of which said free-boardsection rests with the walls of the cathode spaced from the walls of thetank, a tubular anode occuying the space in said cathode with its side,

ottom and end faces confronting but spaced from the corresponding Wallsof said cathode, and insulators resting on the bottom wall of thecathode for supporting said anode.

11. In an electrolytic cell, in combination, a cathode formed as arectangular metal basket with erforated end and side walls, a porousdiap ragm covering the inner faces of said Walls, and an anode occupyingthe space within the cathode and comprising spaced longitudinal sidebars and end bars occupying the spaces between and secured to the endsof said longitudinal bars, all to form active faces confronting andspaced from the active faces of the perforated side and end walls of thecathode.

12. An electro] tic cell comprising a cathode consisting ofy asheet-metal rectangular basket having perforated active side, end andbottom. walls, a rectangular tubular anode having spaced longitudinalside bars and end bars between and secured to the ends of said sidebars, all spaced from the end, bottom and side walls of the cathode,said side and end bars being below the top of the cathode, insulatorsresting on the bottom of the cathode for supporting the anode, and rodsbetween and secured to said anode-side-bars for conducting the electriccurrent thereto.

13. An electrolytic cell comprising a cathode consisting of asheet-metal rectangular basket having perforated active side, end andbottom walls, a tubular anode having spaced longitudinal side bars andend bars 'between and secured to the ends of said side bars, all spacedfrom the end, bottom and side walls of the cathode, said side and endybars being below the top of the cathode, in-

sulators resting on the bottom of the cathode for supporting the anode,rods Vbetween and secured to said anode-side-bars for conducting theelectric current thereto, and an extension from one of the Walls of saidcathode for conducting the current therefrom.

1l. In an electrolytic cell, in combination` a cathode formed as arectangular metal basket with perforated end and side Walls, a porousdiaphragm covering the inner faces of said walls, an anode occupying thespace within the cathode and comprising spaced longitudinal side barsand end bars occupying the spaces between and secured to the ends ofsaid longitudinal bars, all to form active faces confronting and spacedfrom the active faces of the perforated side and end walls of thecathode, a tank provided with draining means to prevent the accumulationof effluent therein, a free-board section adapted to rest upon the tank,and meansl for clam ing said cathode to the under side of saidfree-hoard section to suspend it therefrom, with the bottom, side andend walls of the cathode spaced from the walls of said tank, wherebysaid cathode is exteriorly unsubmerged.

l5. An electrolytic cell comprising an upper closed free-board section,a metallic basket-like cathode attached to and suspended therefrom by asubstantially liquidtight joint and having perforated side, bottom andend Walls furnishing active faces, a porous diaphragm covering the innerfaces of the cathode, a tubularanode occupying the space Within thecathode and spaced from the inner faces of the end, bottom and sidewalls thereof with its upper edges free to permit the electrolyte toflow thereover, a tank on Which the free-board section rests with thecathode suspended therein and spaced from the Walls thereof, and meansfor withdrawing the effluent from said tank' to prevent the submergenceof the cathode therein, said parts being so arranged that the level ofthe electrolyte in the free-board Section may be abovel the top of thetank to increase the hydrostatic pressure.

In testimony whereof we have affixed our signatures.

HERBERT I. ALLEN. KENT R. FOX.

